Counterbalanced lamp



Oct. 18, 1966 E. KIRKEBY COUNTERBALANCED LAMP Filed March 11, 1964 INVENTORI EIVIND KIRKEBY BY WW ATTORNEYS United States Patent 3,280,322 COUNTERBALANCED LAMP Eivind Kirkeby, Gladengveien 14, Oslo, Norway Filed Mar. 11, 1964, Ser. No. 351,050 Claims priority, application Norway, May 13, 1963, 148,647 Claims. (Cl. 24052) The invention relates to an arrangement of working lamps of the type which consist of a lamp foundation which can be secured to the edge of a table, a machine or the like, comprising a housing in which is mounted a spring-balanced lamp arm consisting of two members. Such lamp arms are usually counterbalanced by aid of an eccentric connection and tension screw springs, so that the lamp arm by its counterbalancing can be adjusted and kept in position at a desired angle.

The object of the invention is to provide a new and serviceable eccentric and spring arrangement for such lamps.

By the new eccentricand spring-loading arrangement is obtained a considerable simplification of the construc tion of such lamps, at the same time as these may be produced with fewer construction parts. Lamps made according to the invention can thus be produced in a simpler and cheaper way than the previously known constructions, while an effective counterbalancing is obtained of the two members of the lamp arm by any adjustment of these members.

For a better understanding of the invention reference is had to the drawing, where an embodiment is schematically shown.

By 1 is designated the upper part of the support, i.e. the housing in which is mounted the jointed lamp arm. The innermost or lower arm 3 is coupled to the outer or upper arm 4 by aid of the wrist pin or pivot pin 5. The right-hand end of the upper arm 4 and the central portion of the lower arm 3 are cut away.

The bottom portion of arm 3 extends through a slot in the top of housing 1 and is pivoted upon a spindle or pivot pin 2 rigidly mounted on the housing. The pivotal mounting of arm 3 is through an eccentric disk 8 fixed to the arm and journaled on pivot pin 2, and having an annular peripheral surface. An outer eccentric disk 7 is journaled on the peripheral surface of eccentric disk 8 and has an annular peripheral surface. Hence, the two eccentric disks may turn together around the fixed axis of pivot pin 2, or the disks may rotate independently of each other with either one being stationary and the other moving, or they may move at different rates and in the same or opposite directions. During such rotary or swinging movement of the eccentric disks, the eccentric axis of disk 8 moves around the fixed axis of pivot pin 2, and the eccentric axis of disk 7 moves around the movable eccentric axis of disk 8. A draw bar or rod 6 is positioned within arm 3 and is pivotally connected at its lower end to eccentric disk 7 by a pivot pin 9; and, at its upper end, it is connected to upper arm 4 by a pivot pin 6'. A tension spring is positioned within housing 1 and is anchored at its lower end, and at its upper end there is an integral hook portion 10'. Hook portion 10' rests upon the top peripheral surface of eccentric disk 7 so as to provide a saddle-like interconnection between the spring and the eccentric disks.

With this arrangement, the clockwise rotation of either of arms 3 or 4 from its position shown moves the hook portion 10 of the spring upwardly, thus to extend the spring. That is, the clockwise swinging movement of arm 3 turns eccentric disk 8 around pivotal pin 2 so as to move the pivotal mounting of the outer eccentric disk 7 upwardly, and that lifts hook portion 10' and increases 3,280,322 Patented Oct. 18, 1966 ice the length or extension of the spring. Also, the clockwise movement of arm 4 acts through draw bar or rod 6 to turn the outer eccentric disk 7 clockwise about disk 8, and that raises the hook portion 10' and increases the length of spring 10.

The direction of the force exerted by spring 10 upon the peripheral surface of disk 7 is generally from the axis of pivot pin 2 toward the Zone within which the eccentric axes move during the swinging of arms 3 and 4.

The two eccentric disks 7 and 8 are arranged in relation to arms 3 and 4 so that there is maximum expansion of spring 10 when the arms are substantially horizontal. Hence, the maximum expansion and tension of the spring counterbalances the maximum moment of force produced by the lamp and arm structure. Movement of either of the arms from the horizontal position reduces this moment of force, and there is a corresponding reduction in the expansion and tension of the spring. It is thus seen that the spring 10 provides separate counterbalancing forces for each of the arms. The relative counterbalancing forces for the two arms throughout the ranges of the swinging movements may be varied as required. The construction is simple and sturdy, and yet is efiicient and dependable at all times.

It will be understood that the arrangement shown in the drawing and described above is only meant to illustrate the inventive idea, and that this can be applied in several other ways. Thus the spring 10 may be replaced by other spring means working against the outer eccentric disk.

What is claimed is:

1. In a construction of the character described, the combination of, a base structure, an eccentric pivot structure, a first arm pivotally mounted at one end upon said base structure by said pivot structure to swing around a horizontal axis, a second arm pivoted at one end upon said first arm to swing about a horizontal axis remote from the pivotal mounting of said first arm, said pivot structure including pivot means fixed to said base structure and an eccentric fixed to said first arm to swing therewith and presenting a first eccentric peripheral surface whereby the swinging of said fixed arm moves the axis of said peripheral surface, a second eccentric swingably mounted upon said first eccentric peripheral surface and presenting a second eccentric peripheral surface, the axis of which is moved by swinging movement of said second eccentric linkage means interconnecting said second eccentric with said second arm at a pivot spaced from the pivotal connection between said first arm and said second arm whereby the pivotal movement of said second arm rotates said second eccentric about said first eccentric peripheral surface, and a spring operatively mounted to exert resilient force against said second eccentric peripheral surface to produce counterbalancing forces upon both of said eccentrics.

2. The combination as described in claim 1, wherein said spring is a tension spring exerting force generally in the direction from the axis of said pivot means toward the centers of said eccentric surfaces, and hook means extending around and resting upon said second eccentric surface.

3. The combination as described in claim 1 wherein said base structure includes a housing having a slot therein through which said first arm extends and wherein said linkage means is a rod extending longitudinally within said first arm.

4. Apparatus of the character described wherein two arms are pivoted together in end-to-end relationship with the first arm having its other end pivoted upon a base structure and with the other end of the other arm providing support for a lamp or other structure, that im- 3 provement which comprises, a counterbalance structure including, a first eccentric and a second eccentric positioned together and resilient means, and producing a resilient force, said first eccentric being fixed to said first arm and having a pivot axis which is fixed with respect to said base structure and a first eccentric peripheral surface with a first eccentric axis which is moved around said pivot axis by the swinging of said first arm, said second eccentric being rotatably mounted upon said first peripheral eccentric surface and presenting a second peripheral eccentric surface with a second eccentric axis which is moved around said first eccentric axis by the turning movement of said second eccentric, said resilient means including pressure means resting upon said second peripheral eccentric surface thereby to operatively connect said spring means to said eccentrics, said structure also including linkage means connecting said second eccentric to said second arm whereby swinging move- 5 the general direction from said pivot axis toward the zone of said eccentric axes.

References Cited by the Examiner UNITED STATES PATENTS 1/1954 De Wiess 248280 FOREIGN PATENTS 574,751 4/1933 Germany.

15 NORTON ANSHER, Primary Examiner.

CHARLES R. RHODES, Assistant Examiner. 

1. IN A CONSTRUCTION OF THE CHARACTER DESCRIBED, THE COMBINATION OF, A BASE STRUCTURE, AN ECCENTRIC PIVOT STRUCTURE, A FIRST ARM PIVOTALLY MOUNTED AT ONE END UPON SAID BASE STRUCTURE BY SAID PIVOT STRUCTURE TO SWING AROUND A HORIZONTAL AXIS, A SECOND ARM PIVOTED AT ONE END UPON SAID FIRST ARM TO SWING ABOUT A HORIZONTAL AXIS REMOTE FROM THE PIVOTAL MOUNTING OF SAID FIRST ARM, SAID PIVOT STRUCTURE INCLUDING PIVOT MEANS FIXED TO SAID BASE STRUCTURE AND AN ECCENTRIC FIXED TO SAID FIRST ARM TO SWING THEREWITH AND PRESENTING A FIRST ECCENTRIC PERIPHERAL SURFACE WHEREBY THE SWINGING OF SAID FIXED ARM MOVES THE AXIS OF SAID PERIPHERAL SURFACE, A SECOND ECCENTRIC SWINGABLY MOUNTED UPON SAID FIRST ECCENTRIC PERIPHERAL SURFACE AND PRESENTING A SECOND ECCENTRIC PERIPHERAL SURFACE, THE AXIS OF WHICH IS MOVED BY SWINGING MOVEMENT OF SAID SECOND ECCENTRIC LINKAGE MEANS INTERCONNECTING SAID SECOND ECCENTRIC WITH SAID SECOND ARM AT A PIVOT SPACED FROM THE PIVOTAL CONNECTION BETWEEN SAID FIRST ARM AND SAID SECOND ARM WHEREBY THE PIVOTAL MOVEMENT OF SAID SECOND ARM ROTATES SAID SECOND ECCENTRIC ABOUT SAID FIRST 